At present, eight .alpha.-herpes viruses indigenous to primates are known. Several journal articles describing the Simian herpes viruses have been published (R. N. Hull, The Simian Herpes Viruses in The Herpes Viruses (D. S. Kaplan ed., Academic Press, 1973); K. McCarthy and F. A. Tosolini, Proc. Roy. Soc. Med., 68:11-16 (1975)). Early studies using virus neutralization assays (Hull (1973)) and more recent molecular studies have demonstrated (R. C. Desrosiers and L. A. Folk, J. Gen. Virol,. 56:119-130 (1981); R. Eberle and J. K. Hilliard, J. Virol., 50:316-324 (1984); Mou et al, Arch. Virol. 91:117-133 (1986); R. Eberle et al, Arch. Virol., 109:233-252 (1989); J. K. Hilliard et al, Arch. Virol., 109:83-102 (1989); K. Borchers et al, Arch. Virol., 111:1-14 (1990)) that six of these viruses are closely related to each other. These are the two human herpes simplex viruses, HSV1 and HSV2; a virus indigenous to African monkeys, SA8 (herpes virus cercopithecus); monkey B virus (herpes virus simiae), which is indigenous in Asiatic macaques; herpes virus saimiri 1, which is indigenous in South American squirrel monkeys; and herpes virus ateles 1, which is indigenous in South American spider monkeys. In its natural host species, B virus causes self-limiting oral and genital lesions similar to those produced in humans by HSV1 and HSV2 (S. A. Keeble, Ann. N.Y. Acad. Sci., 85:9960-9969 (1960); H. T. Zwartouw and E. A. Boulter, Lab. Anim., 18:65-70 (1984); H. T. Zwartouw et al, Lab. Anim., 18:125-130 (1984)). Humans can contract B virus by bites or scratches inflicted by macaques (W. L. Davidson and K. Hummeler, Ann. N.Y. Acad. Sci., 85:970-979 (1960). In humans, untreated B virus infections are severe and usually fatal (A. B. Sabin and A. M. Wright, J. Exp. Med., 59:115-136 (1934); S. P. Nagler and M. Klotz, Canad. Med. Assoc. J., 79:743-745 (1958); E. C. Pierce et al, Am. J. Hyg., 68:242-250 (1958); Centers for Disease Control, MMWR, 36:289-296 (1987); S. S. Kalter and R. L. Heberling, Lab. Anim., 18:31-34 (1989). In recent cases of human B virus infection, experimental drug therapy has been effective at preventing mortality. However, the experimental nature of these drugs and the duration over which they must be used necessitates definitive B virus diagnosis prior to their use. The severe nature of B virus infections in humans has resulted in attempts, both past and ongoing, to establish B virus-free colonies of macaques for research use. Identification of B virus infected monkeys is an integral part of establishing such colonies.
B virus is closely related to both the human HSVs and to SA8 (J. K. Hilliard et al, Arch. Virol., 93:185-198 (1987); Hilliard et al, (1989); Eberle et al, (1989)). Most humans have antibodies to HSV1 and/or HSV2, most adult macaques have antibodies to B virus, and most adult baboons have antibodies to SA8. Since antibodies to any one of these viruses will react with all four of these viruses, it is difficult to serologically diagnose the virus by which the antibodies were originally induced (i.e., the virus with which an individual is infected). Using sensitive and specialized assays, this can be done, albeit with considerable time, expertise, specialized biocontainment and expense (D. Katz et al, J. Virol. Methods, 14:99-109 (1986); R. Heberling and S. S. Kalter, Lab. Anim. Sci., 37:304-308 (1987)). Similarly, currently employed techniques for identification of B virus or SA8 in clinical specimens requires not only the considerable time and expense associated with performing virus isolations but also additional testing to determine whether the virus isolated is HSV 1, HSV2, B virus, or SA8 (R. Eberle and D. Black, Arch. Virol., 118:67-86 (1991); J. K. Hilliard et al, J. Virol Methods, 13:55-62 (1986)). In addition, there are strict regulations regarding the biosafety containment facilities necessary to work with biological samples suspected or known to contain B virus. This currently limits diagnostic activities for B virus in the United States to two laboratories.
B virus (Herpesvirus simiae) infection is an occupational hazard for monkey handlers and those who come into contact with macaque mucosal secretions and/or tissues, e.g., kidney cells frequently used for primary cell culture. Although B virus infections in humans are not common, the increased usage of macaque monkeys in biomedical research, especially AIDS research, has been associated with an increased frequency of human exposure to B virus with four fatalities in the past five years (Centers for Disease Control, MMWR., 36:289-296 (1987); Centers for Disease Control, MMWR., 38:353-354 (1989); J. Med. Primatol., 20:373 (1991)).
B virus, an .alpha.-herpes virus, is enzootic in rhesus (Macaca mulatta), cynomolgus (Macaca fascicularis) and other Asiatic monkeys of the genus Macaca (A. E. Palmer, J. Med. Primatol., 16:99-130 (1987)). It was first isolated in 1934 from a fatal human case following a bite from an apparently normal rhesus monkey (Sabin and Wright, (1934)). B virus is morphologically, biologically, and antigenically similar to herpes simplex virus types 1 and 2 (HSV1 and HSV2). Like HSV1 and HSV2 infections in humans, primary infection with B virus in macaques can result in gingivostomatitis, conjunctivitis or genital infections (Zwartouw and Boulter (1984)). Nonlesional, asymptomatic disease can also occur. Following primary infection, B virus can establish latency in the host and can reactivate spontaneously or in response to stress, resulting in shedding of virus in saliva and/or genital secretions even in the absence of visible lesions (A. D. Vizoso, Br. J. Exp. Pathol., 56:485-488 (1975); E. A. Boulter, J. Biol. Stand., 3:279-280 (1975)). In humans, B virus infection contracted by accidental monkey bite or from infected tissues or body fluids causes acute ascending myelitis, which leads to death from respiratory paralysis (Palmer (1987)). The recent outbreaks orb virus infection in humans, resulting in four fatalities including the demonstration of the first human to human B virus transmission, underscores the importance of rapid diagnosis of infection (CDC (1987); CDC (1989)). Rapid identification of infection permits early antiviral intervention reducing morbidity and mortality.
Currently, the diagnosis of B virus infection is accomplished primarily by isolation and identification of the virus. However, this method of detection requires strict biosafety containment facilities and specialized personnel. Given the high survival-value of antiviral treatments sufficiently early in the course of the disease, a rapid, specific and sensitive diagnostic test is needed. Polymerase chain reaction (PCR) technique (R. K. Saiki et al, Science, 230:1350- 1354 (1985)), which allows the enzymatic amplification of minute quantities of DNA often undetectable by other methods, has been widely used for detection of several viral agents such as HSV (A. H. Rowley et al, Lancet, 335:440-441 (1990)), human immunodeficiency virus (HIV) (C-Y Ou et al, Science, 239:295-297 (1988)) and human papilloma viruses (HPV) (D. Shibata, J. Exp. Med., 167:225-230 (1988)). The applicants herein use PCR for detection of B virus in human and monkey samples.
Concern about the occupational health hazards associated with handling monkeys infected with B virus, as well as other zoonotic infections, has led to a recognized need for B virus-free breeding colonies. The increased usage of macaques in biomedical research underscores the importance for rapid diagnosis of B virus infections. The recent human fatalities might each have been avoided by early diagnosis. To date, laboratory diagnosis of B virus infection has been achieved primarily by virus culture. After virus isolation in suitable cell lines, the identification of the virus is accomplished either by neutralization assay (G. W. Gary and E. L. Palmer, J. Clin. Microbiol., 5:465-470 (1977)) or by molecular biology assays. Virus neutralization assays are cumbersome, time consuming and tedious. Furthermore, they often yield equivocal results. Using molecular biology assays, virus identification and differentiation can be performed by i) analysis of infected-cell polypeptides on SDS-polyacrylamide gels (Hilliard et al (1987)), or ii) restriction-endonuclease analysis of infected-cell DNA (Hilliard et al, J. Virol. Methods, 13:55-62 (1986); L. V. M. Wall et al, Virus Res., 12:283-296 (1989).
Such molecular biology assays for the purpose of diagnosis of monkey B virus infection can only be performed if the exact sequence of monkey B virus DNA and the proteins for which it codes are known and, furthermore, a method is devised for separating out and identifying the monkey B virus DNA and/or protein sequences from the infected cells. Before the present invention, the necessary sequence data and such a method for separating and identifying monkey B virus DNA from infected cells has not been known or obtainable.